The only person who can tell what sexuality a person is, is the person involved. Everybody else is clueless.
I was searching for something yesterday on the web when I stumbled on an interview with Kirstie Alley, from a couple of years ago. She was talking about John Travolta and responding to the rumors about his being gay. She said he’s not gay. She is quoted saying he is “the great love of my life.” And then she is quoted saying, “I know John. With all my heart and soul, he’s not gay.” Alley is talking about things she knows nothing about. She doesn’t know John. Nobody can, but John.
Apparently she had sex with Travolta, and she thinks that gives her authority to speak of his sexuality. It doesn’t. Some men can’t operate outside their sexuality. Others—many others—can. It works like this: A man knows what his default sexuality is, he likes men, but society brings pressure to bear on him not to like men, which the man gives in to. Or having a relationship with a woman gives the man something he doesn’t get otherwise. Or it may be that the man falls in love with her, and he enters into a relationship with her. No one knows what it is but the man involved.
During the whole of the life the man spends with this woman, no one sees evidence of the man’s default sexuality. It may be that he will die in this state, or it may be that at some point he will announce that he is leaving his relationship and is prepared to explore sex with men.  All of this is so deeply private—it’s happening in a place so far removed from any other person’s perception—that none of the rest of us can say anything about the process. We can’t tell what’s happening in another man’s brain or heart.
A man I am distantly related to was trying to get his head around parts of my life and having difficulties. He said, worried look on his face, “Well, all those years you were in a marriage, you must have been—” and here he paused, searching for a word, “—at least bisexual.” He wanted me to say yes, in which case I could be inserted into a familiar pattern, and he could stop thinking about these difficult matters.
But I said, “No. Never during all those years did I stop being gay, and never did I develop a feeling for women. I was never anything more than a gay man.” What I tried to go on and explain to him was that gay was more complicated than our culture would have it. And some can be profoundly gay and completely gay and yet at the same time can function for a time as something else. It’s not that I “functioned” for eighteen years as something else. It’s that I did what I had to do for tonight. And then I did it again tomorrow night. I did this for myself and also because I cared about her. But afterward I went back to being Dwight Cathcart, queer the rest of the time even though no one knew about it. Most of the things in life that are worth having are the result of tradeoffs. You give up something important in order to get something more important. I loved her, and, for a number of years I gave up my own sexuality in order to live with her. And to have my children. At that time, that was the way it was done.